Apparatus for regulating the speeds of driven units in machine tools or the like

ABSTRACT

The rate of delivery of two axial piston pumps is adjustable by the cores of two flexible shafts each of which can change the inclination of a pivotable part in the respective pump. The cores carry followers movable in slots provided in the arms of a lever which is pivotable to thereby change the delivery of one or both pumps. The lever can be pivoted by a reciprocable holder having two forks which guide the followers and move them toward or away from the axis of the lever in response to displacement of the holder. This causes adjustment of one of the pumps because one of the followers is normally held against movement in a direction to move the corresponding core axially. The pumps can be adjusted simultaneously if the one follower is moved by a slide to thereby pivot the lever and cause the other follower to move the corresponding core lengthwise to the extent determined by selected distances between the axis of the lever and the followers.

United States Patent [72] Inventor Heinz Hartkopf Solingen, Germany [21]Appl. No. 9,785 [22] Filed Feb. 9,1970 [45] Patented Nov. 9, 1971 [73]Assignee Th. Kieserling & Albrecht Werkzeugmaschlnenfabrik Solingen,Germany [32] Priority Feb. 11, 1969 [33] Germany [31] Pl906651.4

[54] APPARATUS FOR REG ULATING THE SPEEDS 0F DRIVEN UNITS IN MACHINETOOLS OR THE LIKE 10 Claims, 8 Drawing Figs.

[52] US. Cl 417/426, 74/469, 74/480, 417/429 [51] Int. Cl ..F04b 23/04,F04b 41/06 [50] Field of Search .0 417/425, 426, 429, 222, 427, 428;137/99; 74/469, 480

[56] References Cited UNITED STATES PATENTS 3,116,852 1/1964 Anderson417/429 X Primary ExaminerCarlton R. Croyle Assistant Examiner-Richard JSher Attorney-Michael S. Striker ABSTRACT: The rate of delivery of twoaxial piston pumps is adjustable by the cores of two flexible shaftseach of which can change the inclination of a pivotable part in therespective pump. The cores carry followers movable in slots provided inthe anus of a lever which is pivotable to thereby change the delivery ofone or both pumps. The lever can be pivoted by a reciprocable holderhaving two forks which guide the followers and move them toward or awayfrom the axis of the lever in response to displacement of the holder.This causes adjustment ofone of the pumps because one of the followersis normally held against movement in a direction to move thecorresponding core axially. The pumps can be adjusted simultaneously ifthe one follower is moved by a slide to thereby pivot the lever andcause the other follower to move the corresponding core lengthwise tothe extent determined by selected distances between the axis of thelever and the followers.

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IN VENTOR PATENTEUunv 9 ISTI SHEET 6 [1F 7 IN VEN TOR fir/in HA/Ulw rAPPARATUS FOR REGULATING THE SPEEDS OF DRIVEN UNITS IN MACHINE TOOLS ORTHE LIKE BACKGROUND OF THE INVENTION The present invention relates toapparatus for controlling the operating speeds of driven units inmachine tools or the like, particularly for regulating the speeds ofadvancing and straightening units in a machine for straightening ofelongated tubular or bar stock. Still more particularly, the inventionrelates to improvements in apparatus which can be utilized to effectsimultaneous or independent changes in speeds of two or more units inmachine tools as well as to select and maintain a desired ratio betweensuch speeds.

Many machine tools comprise several groups of elements which must bedriven at difierent speeds and wherein the speed of one group must besynchronized with the speed or speeds of one or more additional groups.For example, a shaving machine for tubes or bars normally comprises arevolving head for one or more cutting tools serving to remove materialfrom the external surface of a workpiece which is fed lengthwise bycarriages, rolls or other advancing means. The rotational speed of thehead must be synchronized with operating speed of the advancing meansbut the ratio between the two speeds must be variable if the machine isto be capable of treating workpieces of ditferent diameters and/or ifthe material of a preceding workpiece is different from the material ofthe next-following workpiece. The machine should be capable ofincreasing and reducing the two speeds but the ratio between the twospeeds should normally remain the same. In certain presently knownshaving machines for tubes or the like, the means for rotating theshaving head and for operating the advancing means comprises a pair ofso-called Leonard drives one of which rotates the head and the other ofwhich transmits motion to the advancing means. The two drives areconnected to each other by an electrical speedregulating device whichinsures that the ratio of the speed of shaving head to the speed ofadvancing means remains unchanged irrespective of changes in r.p.m. ofthe head. Such speed regulating device is disclosed, for example, inGerman Pat. No. 1,187,456. A drawback of Leonard drives and of theaforementioned electrical regulating device is thatthey are too bulky,too complicated and too expensive for use in certain types of machinetools.

It is also known to provide a straightening machine for tubes or barswith a first drive for the rotary head which accommodates thestraightening rolls and with a second drive for the advancing means(rolls or carriages) which transports the workpieces toward and awayfrom the revolving head. In certain instances, the two drives receivetorque from a variablespeed transmission which can simultaneously changethe speeds of both drives but leaves the ratio between such speedsunchanged. If the drives are independent of each other, synchronizationof movements of the head and advancing means presents serious problems.On the other hand, if the two drives receive torque from avariable-speed transmission, the ratio of the two speeds remainsconstant at all times which afi'ects the versatility of thestraightening machine because the operator is unable to vary the speedof the revolving head independently of the speed of the advancing means.Such adjustment is necessary if the diameters of workpieces vary.

SUMMARY OF THE INVENTION An object of the invention is to provide asimple, compact and reliable apparatus which can be used in machinetools or the like to control the speeds of two or more driven units insuch a way that the ratio between the speeds of the units can remainconstant even if the speeds are increased or reduced, and which furtherpermits adjustments in the speed of one unit independently of the otherunit or units.

Another object of the invention is to provide an apparatus of the justdescribed character which is particularly suited for use instraightening machines for tubes, bars or analogous workpieces and whichcan effect an infinite number of adjustments in the ratio betweenseveral speeds as well as an infinite number of adjustments of the speedof a given unit.

A further object of the invention is to provide an apparatus which canbe installed in or combined with existing machine tools. I

An additional object of the invention is to provide an apparatus whichis particularly suited for regulating the speeds of hydraulic orpneumatic drive means in machine tools or the like.

The improved apparatus is used for effecting simultaneous as well asindependent changes in operating speeds of driven units, particularly(but not exclusively) for regulating the speeds of straightening andadvancing units in a machine for straightening or tubular or bar stock.It comprises first and second drive means respectively including firstand second variable delivery pumps each having an adjustable partmovable between a plurality of positions to thereby vary the delivery ofthe respective pump, movable first and second mechanical adjustingdevices each connected with one of the adjustable parts, and controlmeans for moving the adjusting devices simultaneously or independentlyof each other. The control means comprises a control member which ispivotable about a predetermined axis and includes first and second arms,and shifter means operative to respectively establish operativeconnections between the first and second adjusting devices and the firstand second arms at selected distances from the axis. Such distancesdetennine the ratio between the delivery rates of the two pumps. Thecontrol member pivots in response to movement of one of the adjustingdevices to thereby move the other adjusting device to a desired extent.Furthermore, the other adjusting device can be moved in response to suchpivoting of the control member which does not result in movement of theone adjusting device in a direction which results in adjustment of thecorresponding pump. Thus, by the simple expedient of moving the shiftermeans, the operator can change the speeds of the two pumps withoutchanging the ratio of their speeds. On the other hand, by pivoting thecontrol member while one of the adjusting devices is held against suchmovement which results in adjustment of the corresponding pump, theother adjusting device can be moved to adjust the corresponding pump.One of the pumps can drive a motor for the head of a straighteningmachine and the other pump can drive the carriages or rolls whichtransport workpieces lengthwise toward and away from the head.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved apparatus itself, however, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the following detaileddescription of certain specific embodiments with reference to theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic plan view of anapparatus which is combined with a straightening machine and serves toregulate the speeds of means for advancing and straightening theworkpieces;

FIG. 2 is an enlarged plan view of the control means for the pumps inthe apparatus shown in FIG. 1;

FIG. 3 is a transverse sectional view as seen in the direction of arrowsfrom the line CD of FIG. 2;

FIG. 4 is a transverse sectional view as seen in the direction of arrowsfrom the line A-B of FIG. 2;

FIG. 5 is a sectional view as seen in the direction of arrows from theline E-F of FIG. 2;

FIG. 6 is a view as seen in the direction of arrow X shown in FIG. 5;

FIG. 7 is a partly elevational and partly sectional view of one of thevariable delivery pumps shown in FIG. 1; and

FIG. 8 is an enlarged view of certain details in the pump shown in FIG.7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I,there is shown a portion of a straightening machine for bars 9 oranalogous elongated workpieces. The machine comprises a first drivenunit including a revolving head or basket 1 for straightening rolls 2which orbit about the axis of the workpiece 9 while the latter is fedlengthwise. The drive means for rotating the head 1 comprises ahydraulic motor which drives a pulley 3a by way of a clutch 4. Thepulley 3a drives a pulley 3b of the head 1 by way of endless V-belts 3.The motor 5 is connected with a first pump 6 by means of a supplyconduit 50 and a return conduit 5b. The pump 6 is an axial piston pumpof the variable delivery type and comprises a tank of reservoir 6A foroil or another suitable hydraulic fluid, and an adjustable part 6a whichis accommodated in the tank 6A and is turnable about the common axis oftwo trunnions 6b. The means for pivoting the adjustable part 60comprises a mechanical adjusting device here shown as a flexible shaft18 having an axially displaceable core 18a. The arrangement is such thatthe delivery of the pump 6 varies in response to changes in angularposition of the part 6a with reference to the axis of the trunnions 6b.The rotary components of the pump 6 are driven by the output shaft of anelectric motor 17.

The straightening machine further comprises a second driven unitincluding two sets of advancing rolls 7, 7a and 8, 8a which are mountedin frames 7b, 8b respectively located upstream and downstream of thehead 1. These advancing rolls are driven by a second hydraulic drivemotor 10 by way of a clutch 10c, bevel gear transmissions 11-1 1a,12-12(1, Cardan shafts 13, 15 and a connecting shaft 14. The motor 10 isconnected with a second variable delivery pump 16 which is mountedmirror symmetrically with reference to the pump 6 and is of identicaldesign. Its adjustable part 16a is pivotable about the common axis oftrunnions 16b by the core 190 of a second flexible shaft 19. The tank ofthe pump 16 is shown at 16A. The connection between the pump 16 and themotor 10 comprises a return conduit 10b and a supply conduit 10a. Theframes 7b, 8b accommodate transmissions (not specifically shown) whichinsure that at least one roll of each set of advancing rolls is drivento transport the workpiece 9 in a direction from the left to the right,as viewed in FIG. I, and to hold the workpiece against rotation.

The end portions 18b, 19b of the cores 18a, 19a of the flexible shafts18, 19 are connected with shafts 24, (FIGS. 2-6) for roller followers18c, 19c received in elongated guide portions or slots 20, 21 of arms22a, 22b forming part of a twoarmed control lever 22 turnable on a pivotpin 23 of a support or housing 30. The shafts 24, 25 respectively carrypairs of rollers 24a, 24b and 25a, 25!: (FIG. 5) which extend into thespaces between the prongs of two forks 26a, 26b forming part of ashifter or holder 26 which is further provided with wheels 26c arrangedto travel along rails or ways 29 provided in the housing 30. The holder26 has a median portion 26d which constitutes a toothed rack and mesheswith a gear 27 on a shaft 27a. Thus, the gear 27 can reciprocate theholder 26 along the rails 29 to thereby move the followers 18c, 19clengthwise of the respective guide slots 20, 21 in the control lever 22.The shaft 270 can be rotated by a handwheel or knob 28. Such rotationchanges the effective length of the arms 22a, 22b of the control lever22 by changing the distance between the pivot 23 and the shafts 24, 25.This changes the ratio of rotational speed of the head 1 to rotationalspeed of the advancing rolls 7-8b because the shafts 24, 25 cause thecores 18a, 19a of the shafts 18, 19 to change the delivery of pumps 6,16.

The shaft 25 carries a further roller 31 which is received in theelongated guide slot 32 of a displacing member here shown as a slide 33which is reciprocable in the housing in parallelism with the end portion19b of the core 19a in shaft 19 (see FIG. 4). A feed screw which mesheswith the slide 33 carries a knob or handwheel 34 which can be rotated byhand to thereby move the slide 33 and the shaft 25 transversely of thearm 22b and to change the inclination of the control lever 22. This alsocauses an axial displacement of the end portion 18b of the core 18a (byway of the shaft 24) so that an adjustment in delivery of the pump 16effects an appropriate adjustment of delivery of the pump 6. Rotation ofthe knob 34 can change the angular position of the lever 22 in aciockwise or in a counterclockwise direction (compare FIGS. 2 and 6).

The operation:

In the positions shown in FIG. 1, the pumps 6, 16 do not circulate anyfluid because their adjustable parts 6a, are shown in starting orneutral positions. The motors 5, 10 will receive pressurized fluid torotate the head 1 and the advancing rolls 7-80 in response to pivotingof adjustable parts 6a, 160 from their neutral positions. The ratio ofr.p.m. of the head 1 to r.p.m. of the advancing rolls 7-80 depends onthe diameter of the workpiece 9. Such ratio can be selected, as afunction of the diameter of the workpiece 9, by rotating the knob 28,for example, until the effective lengths of the arms 22a, 22b of thecontrol lever 22 correspond to those shown in FIG. 2, i.e., so that theshafts 24, 25 are moved as a unit in response to rotation of the gear 27whereby the shafts 24, 25 are respectively shifted toward or away fromthe pivot pin 23 by the forks 26a, 26b of the holder 26.

The pumps 6, l6 begin to deliver pressurized fluid as soon as theoperator begins to rotate the knob 34 which changes the inclination ofthe control lever 22 and thereby moves the parts 60, 160 from theirneutral positions (for example, the knob 34 will move the control lever22 from the position of FIG. 2 to that shown in FIG. 6). The quantity ofpressurized fluid delivered by pumps 6, l6 depends on the inclination ofthe control lever 22 but the ratio or quantity delivered by pump 6 toquantity delivered by pump 16 is regulated by the knob 28.

If the straightening machine is to thereupon treat a workpiece whosediameter exceeds or is less than that of the workpiece 9, the operatorcan change the r.p.m. of the head 1 without changing the rotationalspeed of advancing rolls 7-80. This is achieved by rotating the knob 28whereby the position of the slide 33 remains unchanged while the controllever 22 pivots on the pin 23. This causes a change in inclination ofthe part 6a to change the delivery of the pump 6. When the control lever22 pivots, the roller 31 on the shaft 25 moves in the slot 32 of theslide 33 (which is parallel to the rails 29, see FIG. 6) so that theposition of the core does not change, i.e., the pump 16 and motor 10continue to drive the advancing rolls 7-8a at an unchanging speed butthe speed of the head 1 changes because the am 220 of the control lever22 changes the axial position of the core 18a and thereby changes theinclination of the adjustable part 6a in the pump 6. Thus, the ratio ofthe speed of advancing rolls 7-8a to the speed of the head 1 can bechanged by rotating the knob 28 which controls the axial position of theholder 26 and hence the distance between the pivot pin 23 and shafts 24,25 (effective length of arms 22a, 22b of the control lever 22). Thespeeds of motors 5, 10 can be changed simultaneously by rotating theknob 34 which moves the slide 33 and thereby pivots the control lever 22by way of the roller follower 190 on the shaft 25. The holder 26 can bemoved lengthwise without pivoting the control lever 22 when the axes ofthe shafts 24, 25 are coplanar with the axis of the pivot 23 (see FIG.2).

An advantage of the improved control apparatus is that the ratio ofrotational speeds of the motors 5, 10 can be selected and the speed ofone of these motors changed infinitely by resorting to very simplemotion transmitting means.

The sheaths 18A, 19A (FIG. 2) of the flexible shafts 18, 19 areconnected to the holder 26 on the one hand and to tanks 6A, 16A on theother hand. As clearly shown in FIGS. 2 and 6, the cores 18a, 19a moveaxially only if the respective shafts 24, 25 are caused to move at rightangles to the rails 29. The shaft 25 can move at right angles to suchrails only if the slide 33 is moved toward or away from the rails; thisis due to the fact that the roller 31 on the shaft 25 extends into theguide slot 32. On the other hand, the shaft 24 can move at right anglesto the rails 29 as soon as it is moved lengthwise of the slot 20provided that the control lever 22 is not held in the neutral positionof FIG. 2. Therefore, the core 180 will move axially as soon as thecontrol lever 22 pivots or as soon as the holder 26 moves lengthwise inother than the neutral position of the control lever, but the core 19amoves axially only in response to manipulation of the knob 34. Theextent of lengthwise (axial) movement of the core 190 always equals theextent of movement of the slide 33 but the extent of axial movement ofthe core 18a depends on the distance between the pivot pin 23 and shaft24 (effective length of the arm 220) as well as on the extent of angulardisplacement of the control lever 22, either in response to movement ofthe slide 33 or in response to movement of the holder 26. Thus, theholder 26 can effect axial movement of the core 180 (pivoting of theadjustable part 6a but it cannot change the axial position of the core190 (angular position of the part 16a).

If the cores 18a, 19a are respectively connected with the shafts 25, 24,the speed of the pump 16 and advancing rolls 7-8a can be changedindependently of the rpm. of the head 1. Also, the pumps 6, 16 can beutilized to drive motors in other types of machine tools, for example,in a shaving machine for tubes, bars or the like.

Flexible shafts which can be used in the apparatus of my invention areavailable on the market under the trade name Flexball (produced byVofa-Werk of Diisseldorf-Oberkassel, Western Germany).

FIGS. 7 and 8 illustrate a portion of the pump 6 and motor 17. Theoutput shaft 17a of the motor 17 carries a disc 50 which is coupled topistons 51 reciprocable in the chambers of a cylinder 52 cooperatingwith a valve plate 53. The cylinder 52 rotates with the pistons 51 andshaft 170 and is accommodated in the casing of the adjustable part 6a.When the latter is pivoted about the common axis of trunnions 6b, thelength of strokes of the pistons 51 changes and the motor 5 receives agreater or a lesser quantity of pressurized fluid. The conduit 50 isconnected to one of the trunnions 6b. The other trunnion 6b admits oilfrom tank 6A to the valve plate 53. The conduit 5b discharges oil intothe tank 6A.

The pump 16 is identical with the pump 6.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

1. In an apparatus for effecting simultaneous as well as independentchanges in operating speeds of driven units, particularly for regulatingthe speeds of straightening and advancing units in a machine forstraightening of tubular or bar stock, a combination comprising firstand second drive means respectively including first and second variabledelivery pumps each having an adjustable part movable between aplurality of positions to thereby vary the delivery of the respectivepump; movable first and second mechanical adjusting devices eachconnected with a different one of said parts; and control means forsimultaneously moving said adjusting devices for simultaneous orindependent movement of said first and second adjustable parts, saidcontrol means including a control member pivotable about a predeterminedaxis and having first and second arms, and shifter means operative torespectively establish operative connections between said first andsecond devices and said first and second arms at selected distances fromsaid axis.

2. A combination as defined in claim 1 wherein each of said adjustableparts is pivotable between said positions thereof and each of saidadjusting devices comprises a motion transmitting element which ismovable lengthwise and comprises a first end portion connected to thecorresponding adjustable part and a second end portion connectable bysaid shifter means to the correspondin arm of said control member.

3. A combination as de med in claim 2 wherein each of said adjustingdevices comprises a flexible shaft including an axially movable coreconstituting the respective motion transmitting element.

4. A combination as defined in claim 2, wherein said arms are providedwith elongated guide portions and the second end portions of said motiontransmitting elements include followers arranged to move lengthwise ofsaid guide portions in response to pivoting of said control member andin response to operation of said shifter means.

5. A combination as defined in claim 4, wherein said shifter meanscomprises a holder which is reciprocable in a direction at right anglesto said axis and comprises a pair of forks each having prongs flankingone of said followers and permitting movement of such followersubstantially at right angles to said direction.

6. A combination as defined in claims 5, wherein each of said followerscomprises a shaft parallel to said axis and further comprising rollersprovided on said shafts and engaging the respective prongs 7. Acombination as defined in claim 5, further comprising means forreciprocating said holder.

8. A combination as defined in claim 7, wherein the means forreciprocating said holder comprises a toothed rack provided on saidholder, a gear meshing with said rack, and means for rotating said gear.

9. A combination as defined in claim 1, wherein said control meansfurther comprises displacing means for moving one of said adjustingdevices to thereby move the other adjusting device by way of saidcontrol member.

10. A combination as defined in claim 1, wherein said arms includeelongated guide portions and each of said adjusting devices comprises afollower arranged to travel along the respective guide portion, saidshifter means comprising a holder reciprocable in a direction at rightangles to said axis and having a pair of forks each including prongsflanking one of said followers and permitting movement of such followerat right angles to said direction, said displacing means comprising aslide movable at right angles to said direction and having guide meansreceiving a portion of one of said followers and extending inparallelism with said direction.

1. In an apparatus for effecting simultaneous as well as independentchanges in operating speeds of driven units, particularly for regulatingthe speeds of straightening and advancing units in a machine forstraightening of tubular or bar stock, a combination comprising firstand second drive means respectively including first and second variabledelivery pumps each having an adjustable part movable between aplurality of positions to thereby vary the delivery of the respectivepump; movable first and second mechanical adjusting devices eachconnected with a different one of said parts; and control means forsimultaneously moving said adjusting devices for simultaneous orindependent movement of said first and second adjustable parts, saidcontrol means including a control member pivotable about a predeterminedaxis and having first and second arms, and shifter means operative torespectively establish operative connections between said first andsecond devices and said first and second arms at selected distances fromsaid axis.
 2. A combination as defined in claim 1 wherein each of saidadjustable parts is pivotable between said positions thereof and each ofsaid adjusting devices comprises a motion transmitting element which ismovable lengthwise and comprises a first end portion connected to thecorresponding adjustable part and a second end portion connectable bysaid shifter means to the corresponding arm of said control member.
 3. Acombination as defined in claim 2, wherein each of said adjustingdevices comprises a flexible shaft including an axially movable coreconstituting the respective motion transmitting element.
 4. Acombination as defined in claim 2, wherein said arms are provided withelongated guide portions and the second end portions of said motiontransmitting elements include followers arranged to move lengthwise ofsaid guide portions in response to pivoting of said control member andin response to operation of said shifter means.
 5. A combination asdefined in claim 4, wherein said shifter means comprises a holder whichis reciprocable in a direction at right angles to said axis andcomprises a pair of forks each having prongs flanking one of saidfollowers and permitting movement of such follower substaNtially atright angles to said direction.
 6. A combination as defined in claims 5,wherein each of said followers comprises a shaft parallel to said axisand further comprising rollers provided on said shafts and engaging therespective prongs.
 7. A combination as defined in claim 5, furthercomprising means for reciprocating said holder.
 8. A combination asdefined in claim 7, wherein the means for reciprocating said holdercomprises a toothed rack provided on said holder, a gear meshing withsaid rack, and means for rotating said gear.
 9. A combination as definedin claim 1, wherein said control means further comprises displacingmeans for moving one of said adjusting devices to thereby move the otheradjusting device by way of said control member.
 10. A combination asdefined in claim 1, wherein said arms include elongated guide portionsand each of said adjusting devices comprises a follower arranged totravel along the respective guide portion, said shifter means comprisinga holder reciprocable in a direction at right angles to said axis andhaving a pair of forks each including prongs flanking one of saidfollowers and permitting movement of such follower at right angles tosaid direction, said displacing means comprising a slide movable atright angles to said direction and having guide means receiving aportion of one of said followers and extending in parallelism with saiddirection.